Installation Manual

16 Introduction and preparation basics
NOTE: HP recommends that you add another 50% as a reserve when calculating the maximum FSC size.
The following examples present space usage for typical configurations.
Example 1: three copies, one generation:
Example 2: two copies, one generation:
Example 3: one copy, one generation:
NOTE: A well defined FSE backup policy with regular backups prevents the excessive growth of the
transaction log files of the File System Catalogs (FSCs). The transaction log files are committed into the
main databases during the FSE backup process.
For details, see the FSE user guide, chapter ”Backup, restore, and recovery”, section ”Backup”.
Formula for the expected Hierarchical Storage Manager Database (HSMDB) size
This is the formula for calculating the maximum Hierarchical Storage Management Database (HSMDB)
size:
where the meaning of the parameters is:
NOTE: A well defined FSE backup policy with regular backups prevents the excessive growth of the
transaction log files of the Hierarchical Storage Management Databases (HSMDBs). The transaction log
files are committed into the main databases during the FSE backup process.
For details, see the FSE user guide, chapter ”Backup, restore, and recovery”, section ”Backup”.
First generation takes (189 for FSC) + (36 x 3 for volume index) = 297 bytes
Each additional generation takes 47 + (36 x 3) = 155 bytes
Total size = ((297 + add. attr. size) x max. number of files) + (155 x number of add. generations)
First generation takes (180 for FSC) + (36 x 2 for volume index) = 252 bytes
Each additional generation takes 38 + (36 x 2) = 110 bytes
Total size = ((252 + add. attr. size) x max. number of files) + (110 x number of add. generations)
First generation takes (162 for FSC) + (36 for volume index) = 198 bytes
Each additional generation takes 20 + 36 = 56 bytes
Total size = ((198 + add. attr. size) x max. number of files) + (56 x number of add. generations)
maxHSMDBsize ..... the maximum HSM database size in bytes.
nf ..... the expected number of files on an HSM file system.
pdi ..... the percentage of directories (%).
afnl ..... the average length of file names in bytes.
pon ..... the percentage of online files (%).
maxHSMDBSize nf 12+()nf pdi× afnl 30+()×[]nf pon× afnl 40+()×[]++=